diff mbox series

[v2,4/9] accel/tcg: Pass last not end to page_set_flags

Message ID 20230317155455.341843-5-richard.henderson@linaro.org
State Superseded
Headers show
Series accel/tcg: Fix page_set_flags and related [#1528] | expand

Commit Message

Richard Henderson March 17, 2023, 3:54 p.m. UTC 
Pass the address of the last byte to be changed, rather than
the first address past the last byte.  This avoids overflow
when the last page of the address space is involved.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1528
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/exec/cpu-all.h |  2 +-
 accel/tcg/user-exec.c  | 16 +++++++---------
 bsd-user/mmap.c        |  6 +++---
 linux-user/elfload.c   | 11 ++++++-----
 linux-user/mmap.c      | 16 ++++++++--------
 linux-user/syscall.c   |  4 ++--
 6 files changed, 27 insertions(+), 28 deletions(-)
diff mbox series

Patch

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 51b6e8594e..db38418d93 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -285,7 +285,7 @@  typedef int (*walk_memory_regions_fn)(void *, target_ulong,
 int walk_memory_regions(void *, walk_memory_regions_fn);
 
 int page_get_flags(target_ulong address);
-void page_set_flags(target_ulong start, target_ulong end, int flags);
+void page_set_flags(target_ulong start, target_ulong last, int flags);
 void page_reset_target_data(target_ulong start, target_ulong end);
 int page_check_range(target_ulong start, target_ulong len, int flags);
 
diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 7b37fd229e..035f8096b2 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -480,24 +480,22 @@  static bool pageflags_set_clear(target_ulong start, target_ulong last,
  * The flag PAGE_WRITE_ORG is positioned automatically depending
  * on PAGE_WRITE.  The mmap_lock should already be held.
  */
-void page_set_flags(target_ulong start, target_ulong end, int flags)
+void page_set_flags(target_ulong start, target_ulong last, int flags)
 {
-    target_ulong last;
     bool reset = false;
     bool inval_tb = false;
 
     /* This function should never be called with addresses outside the
        guest address space.  If this assert fires, it probably indicates
        a missing call to h2g_valid.  */
-    assert(start < end);
-    assert(end - 1 <= GUEST_ADDR_MAX);
+    assert(start <= last);
+    assert(last <= GUEST_ADDR_MAX);
     /* Only set PAGE_ANON with new mappings. */
     assert(!(flags & PAGE_ANON) || (flags & PAGE_RESET));
     assert_memory_lock();
 
-    start = start & TARGET_PAGE_MASK;
-    end = TARGET_PAGE_ALIGN(end);
-    last = end - 1;
+    start &= TARGET_PAGE_MASK;
+    last |= ~TARGET_PAGE_MASK;
 
     if (!(flags & PAGE_VALID)) {
         flags = 0;
@@ -510,7 +508,7 @@  void page_set_flags(target_ulong start, target_ulong end, int flags)
     }
 
     if (!flags || reset) {
-        page_reset_target_data(start, end);
+        page_reset_target_data(start, last + 1);
         inval_tb |= pageflags_unset(start, last);
     }
     if (flags) {
@@ -518,7 +516,7 @@  void page_set_flags(target_ulong start, target_ulong end, int flags)
                                         ~(reset ? 0 : PAGE_STICKY));
     }
     if (inval_tb) {
-        tb_invalidate_phys_range(start, end);
+        tb_invalidate_phys_range(start, last + 1);
     }
 }
 
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index d35650e562..565b9f97ed 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -118,7 +118,7 @@  int target_mprotect(abi_ulong start, abi_ulong len, int prot)
         if (ret != 0)
             goto error;
     }
-    page_set_flags(start, start + len, prot | PAGE_VALID);
+    page_set_flags(start, start + len - 1, prot | PAGE_VALID);
     mmap_unlock();
     return 0;
 error:
@@ -656,7 +656,7 @@  abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
         }
     }
  the_end1:
-    page_set_flags(start, start + len, prot | PAGE_VALID);
+    page_set_flags(start, start + len - 1, prot | PAGE_VALID);
  the_end:
 #ifdef DEBUG_MMAP
     printf("ret=0x" TARGET_ABI_FMT_lx "\n", start);
@@ -767,7 +767,7 @@  int target_munmap(abi_ulong start, abi_ulong len)
     }
 
     if (ret == 0) {
-        page_set_flags(start, start + len, 0);
+        page_set_flags(start, start + len - 1, 0);
     }
     mmap_unlock();
     return ret;
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index bb2001bf30..b068676340 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -212,7 +212,7 @@  static bool init_guest_commpage(void)
         exit(EXIT_FAILURE);
     }
     page_set_flags(TARGET_VSYSCALL_PAGE,
-                   TARGET_VSYSCALL_PAGE + TARGET_PAGE_SIZE,
+                   TARGET_VSYSCALL_PAGE | ~TARGET_PAGE_MASK,
                    PAGE_EXEC | PAGE_VALID);
     return true;
 }
@@ -443,7 +443,7 @@  static bool init_guest_commpage(void)
         exit(EXIT_FAILURE);
     }
 
-    page_set_flags(commpage, commpage + qemu_host_page_size,
+    page_set_flags(commpage, commpage | ~qemu_host_page_mask,
                    PAGE_READ | PAGE_EXEC | PAGE_VALID);
     return true;
 }
@@ -1315,7 +1315,7 @@  static bool init_guest_commpage(void)
         exit(EXIT_FAILURE);
     }
 
-    page_set_flags(LO_COMMPAGE, LO_COMMPAGE + TARGET_PAGE_SIZE,
+    page_set_flags(LO_COMMPAGE, LO_COMMPAGE | ~TARGET_PAGE_MASK,
                    PAGE_READ | PAGE_EXEC | PAGE_VALID);
     return true;
 }
@@ -1727,7 +1727,7 @@  static bool init_guest_commpage(void)
      * and implement syscalls.  Here, simply mark the page executable.
      * Special case the entry points during translation (see do_page_zero).
      */
-    page_set_flags(LO_COMMPAGE, LO_COMMPAGE + TARGET_PAGE_SIZE,
+    page_set_flags(LO_COMMPAGE, LO_COMMPAGE | ~TARGET_PAGE_MASK,
                    PAGE_EXEC | PAGE_VALID);
     return true;
 }
@@ -2208,7 +2208,8 @@  static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot)
 
     /* Ensure that the bss page(s) are valid */
     if ((page_get_flags(last_bss-1) & prot) != prot) {
-        page_set_flags(elf_bss & TARGET_PAGE_MASK, last_bss, prot | PAGE_VALID);
+        page_set_flags(elf_bss & TARGET_PAGE_MASK, last_bss - 1,
+                       prot | PAGE_VALID);
     }
 
     if (host_start < host_map_start) {
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index cf14930c30..9c70f51d97 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -181,7 +181,7 @@  int target_mprotect(abi_ulong start, abi_ulong len, int target_prot)
         }
     }
 
-    page_set_flags(start, start + len, page_flags);
+    page_set_flags(start, start + len - 1, page_flags);
     ret = 0;
 
 error:
@@ -640,15 +640,15 @@  abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
     }
     page_flags |= PAGE_RESET;
     if (passthrough_start == passthrough_end) {
-        page_set_flags(start, start + len, page_flags);
+        page_set_flags(start, start + len - 1, page_flags);
     } else {
         if (start < passthrough_start) {
-            page_set_flags(start, passthrough_start, page_flags);
+            page_set_flags(start, passthrough_start - 1, page_flags);
         }
-        page_set_flags(passthrough_start, passthrough_end,
+        page_set_flags(passthrough_start, passthrough_end - 1,
                        page_flags | PAGE_PASSTHROUGH);
         if (passthrough_end < start + len) {
-            page_set_flags(passthrough_end, start + len, page_flags);
+            page_set_flags(passthrough_end, start + len - 1, page_flags);
         }
     }
  the_end:
@@ -763,7 +763,7 @@  int target_munmap(abi_ulong start, abi_ulong len)
     }
 
     if (ret == 0) {
-        page_set_flags(start, start + len, 0);
+        page_set_flags(start, start + len - 1, 0);
     }
     mmap_unlock();
     return ret;
@@ -849,8 +849,8 @@  abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
     } else {
         new_addr = h2g(host_addr);
         prot = page_get_flags(old_addr);
-        page_set_flags(old_addr, old_addr + old_size, 0);
-        page_set_flags(new_addr, new_addr + new_size,
+        page_set_flags(old_addr, old_addr + old_size - 1, 0);
+        page_set_flags(new_addr, new_addr + new_size - 1,
                        prot | PAGE_VALID | PAGE_RESET);
     }
     mmap_unlock();
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 24cea6fb6a..7fbc664e83 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4594,7 +4594,7 @@  static inline abi_ulong do_shmat(CPUArchState *cpu_env,
     }
     raddr=h2g((unsigned long)host_raddr);
 
-    page_set_flags(raddr, raddr + shm_info.shm_segsz,
+    page_set_flags(raddr, raddr + shm_info.shm_segsz - 1,
                    PAGE_VALID | PAGE_RESET | PAGE_READ |
                    (shmflg & SHM_RDONLY ? 0 : PAGE_WRITE));
 
@@ -4624,7 +4624,7 @@  static inline abi_long do_shmdt(abi_ulong shmaddr)
     for (i = 0; i < N_SHM_REGIONS; ++i) {
         if (shm_regions[i].in_use && shm_regions[i].start == shmaddr) {
             shm_regions[i].in_use = false;
-            page_set_flags(shmaddr, shmaddr + shm_regions[i].size, 0);
+            page_set_flags(shmaddr, shmaddr + shm_regions[i].size - 1, 0);
             break;
         }
     }